Troubleshooting in motor vehicles is one task of motor vehicle workshops. For this purpose, the workshops frequently use so-called diagnostic testers as a technical aid. One task of a diagnostic tester is to communicate with control devices installed in the motor vehicle and read out their fault memory, and another task is to support the troubleshooting. A diagnostic tester is desirable, which supports the mechanic in the troubleshooting, in that the diagnostic tester names possibly defective components and/or generates suggestions for further test steps on the basis of symptoms, fault memory entries, and the tests already carried out on the motor vehicle. The basis for such a functionality of the diagnostic tester is the knowledge of cause-effect relationships between a defective component in the motor vehicle and the effects of the defect on symptoms, fault memory entries, and test results of testing procedures.
One example of a diagnostic system of the type which enables guided troubleshooting is described in German Published Patent Application No. 10 2011 086 352. Workshop experts (“authors”) must maintain the knowledge stored in the diagnostic tester regarding the aforementioned cause-effect relationships between a defective component in the motor vehicle and the effects of the defect on symptoms, fault memory entries, and test results of testing procedures on the basis of their treasure trove of experience. Due to the plurality of makes and variants of motor vehicles, a great deal of effort is required for the authors to manually generate the necessary knowledge base.
Franchised workshops must utilize the diagnostic systems of the particular motor vehicle manufacturer. Guided troubleshooting is based, on the one hand, on the knowledge of diagnostic authors, and on the other hand on empirical knowledge, in that the manufacturers build up case databases, for example, in the form of technical service bulletins, and make these available to the workshops. The two approaches for supporting the mechanic are independent of one another, however.
Case-based databases are becoming established to an increasing extent in the manufacturer-independent “independent aftermarket (IAM)”. The suppliers gather a plurality of repair cases and offer workshops access to their databases, against payment, so that the workshops may research similar cases.
The quality of a diagnostic system for the IAM, which is based solely on case databases, is highly dependent on the actual numbers of cases per motor vehicle and on the overall picture of symptoms. Case-based systems make it possible to reliably detect typical problems on motor vehicles given a suitable number of cases. Due to the plurality of makes and model variants, the actual number of cases, except with respect to mass-produced vehicles, is often small, so that the variance of the suggested causes and defective components is high and, therefore, the desired reliability of the suggestions cannot always be realized.
Building up diagnostic systems for the IAM with the aid of author knowledge is difficult and expensive, on the one hand, due to the plurality of makes and variants, and, in addition, is dependent on the treasure trove of experience of the involved authors. Typical problems of a motor vehicle may be overlooked due to lack of experience on the part of the involved authors, but the reliability and variance of the repair suggestions is high.